Slime-pulp thickener



Apr. 17, 1923. 1,45%(916 c. ALLEN SLINIE PULP THICKENER Filed June -9 1917 WITNESSES: INVENTOR CHARL2; ALLEN BY 3 Patented Apr. 17, 1923.

PATENT CHARLES ALLEN, or EL PASO, T XAS.

SLIME-PULP Application filed June 9,

To all whom it may concern: I

Be it known that 1, CHARLES ALLEN, a citizen of the United States, residing at El Paso, in the county of El Paso andState of Texas, have invented new and useful Improvements in Slime-Pulp Thlckeners, of which the following is a speclfication.

This invention relates to the thickening of slime or pulp.

Thickening, which is a partlal dewatering of finely divided solids in suspension, 1S almost universally used in the treatment of ores by wet milling processes, and inits every application it is of prime importance that the degree of thickening be uniform, that is, that the discharge of the thickened slime bealways of the same density. Thickeners heretofore used depend upon the volume of pulp fed to the cone or tank for regulation of the size of the discharge orifice. The results are very unsatisfactory, inasmuch as the proportions of liquids to solids in the material discharged varies with the volume of slime pulp fed to the thickener. In the present invention, the volume of slime pulp in the thickener in no manner alters the proportion of liquids to sohds 1n the products discharged, within the limits of the capacity of the machine. The degree of thickening is controlled by the increase in specific gravity due to the settling of the material of heavier specific gravity without reference to the volume fed to the thickener, and for whatever degree of thickening the device is adjusted, that degree of thickening is automatically maintained.

In slime pulp, the finely divided solids move freely without appreciably aifecting the fluidity by friction among themselves. Such a pulp has the properties of a liquid so long as the solids are kept in suspension. When the pulp is composed of water and solid particles of greater specific gravity than water, the specific gravity of the pulp increases with all increases in the quantity of solids in suspension in the pulp. This pulp may therefore be considered as a liquid of greater density than water.

In myinvention I employ two connected compartments having in one compartment a liquid and in the other a mixture of liquids and solidsor pulp. The variations in the density of the pulp, due to the presence of more or less solids in suspension, actto 5 raise and lower the column of liquid, which THICKENER.

1917. Serial No. 173,785.

column of liquid carries a float operatively connected to a valve at the bottom of the tank controlling the discharge orifice. When the pulp attains a certain density, the valve is automatically opened to permit the discharge of the thickened pulp through the orifice may vary considerably, but the density of the thickened slime discharged remains practically constant. This is the reverse of the thickeners ordinarily used in which the volume of thickened slime discharged remains constant while the density of the discharge varies with the quantity fed into the thickener.

A form which my invention may assume and illustrated in the accompanying drawmg, in which The figure is a view in central, vertical section disclosing an embodiment of my invention, and particularly illustrating the position and operation of the final elements thereof. H

As here shown the apparatus comprises a tank 10 in the shape of an inverted cone having a discharge orifice 11 at its bottom for carrying OK the thickened product. A. launder 12 is arranged at the top of the tank for carrying oft clear liquid which overflows and a conduit 13 supplies slime pulp to the tank. A float 14, having its buoyancy variable by adjustable weights 15, has operative connections 16 with a valve 17 which controls the discharge orifice, and achamber 18 is provided for the fioat, said chamber extending to a higher level than the normal level of pulp in the tank and being adapted to contain clear water, preferably supplied through a pipe 19. This chamber, is one of two connected compartments a U- shaped conduit of which the tank with its pulp forms the other, the two being so arranged that a hydrostatic balance is maintained between the column of water on the one hand and the pulp on the other. The variations in the density of the pulp outside by the valve 17 until the float becomes buoyant, and in this case that is until the balancing column of liquid in has attained a density of 1.20. Any further increase in the density of the column in 10 causes a corresponding rise of the liquid in 18 and with it rises the now buoyant float 14, which through the connections 16 removes the valve '17 from the spigot 11 through which outflows the thickened material in 10 in quantity proportionate to the area of the spigot opening, which is proportionate to the rise of the float 14:, which rise is in direct proportion to the density of the liquid column in of thickening, but means whereby the float line of the actuating float may be altered must be used in order to be able to adjust the thickener to various degrees of thickening.

Various changes in the construction and arrangement of the several parts herein shown and described may be employed without departing from the spirit of my invention as disclosed in the appended claims.

It is understood wherever the word water is used that I include in that term any other liquid or solution employed in practical mining operations and with pulp to be subjected to my process.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

1. A thickener for slime pulp comprising a vessel havin a bottom discharge orifice for quickly sett ing and heavy particles and a rim overflow for slowly settling and light particles, a valve to control said bottom dis charge orifice, a float column in operative communication with that portion of the vessel where the said material accumulates, means for admitting fluid of fixed density into said column, and a float in said column operatively connected with the valve in the bottom discharge orifice, whereby an increase in density of such accumulated material-due to settling-will act to raise the column of fluid of fixed density and with it the float for the purpose of opening the valve to permit such accumulated material to be discharged.

2. A thickener as set forth in claim 1 having means to vary the float line of the float to cause variation in the density of the discharged product.

3. A thickener for solids suspended in liquid, and which suspension varies in density from time to time, comprising a settling vessel having a bottom orifice for the dis charge of quickly settling and heavy particle and open at its top to permit the slowly settling and light particles to overflow the rim, a valve to control the bottom discharge orifice, a float column having an outlet open: ing into said vessel, a float in said column operatively connected to the valve, means for supplying fluid of a fixed density to the float column, and means opening into the vessel exterior of the float column for supplying material to be treated thereto, whereby when the settled material in the vessel has acquired a suflicient density to obstruct the outlet on the float column the latter becomes filled with fluid of a fixed density and causes the float to rise thereby opening the valve.

4. A thickener for solids suspended in liquid, and which suspension varies from time to time, comprising a conical settling tank having its apex at the bottom and formed with an orifice for the discharge of heavy and quickly settling particles and being open at its top to permit light and slowly settling particles to overflow its rim. a valve to control the bottom discharge orifice, a float chamber extending from a point above the top of the tank down into the interior thereof and open at its lower end, a float in said chamber operatively connected with the valve, means for continuously supplying clear water to the float chamber, and means opening into the tank outside the float chamber for supplying material to be, treated, whereby when the settled material in the tank has acquired a suflicient density to obstruct the bottom of the float chamber the latter will become filled with fluid of a fixed density, thereby lifting the float and causing the valve to be opened.

In testimony whereof I have hereunto set my hand in the presence of two subscribing witnesses.

CHARLES ALLEN. l/Vitnesses A. H. Swn'rr, EDMUND SHAW. 

